Induction of labor and cesarean birth in lower-risk nulliparous women at term: A retrospective cohort study.

OBJECTIVE: To evaluate whether induction of labor (IOL) is associated with cesarean birth (CB) and perinatal mortality in uncomplicated first births at term compared with expectant management outside the confines of a randomized controlled trial. METHODS: Population-based retrospective cohort study of all births in Victoria, Australia, from 2010 to 2018 (n = 640,191). Preliminary analysis compared IOL at 37 weeks with expectant management at that gestational age and beyond for uncomplicated pregnancies. Similar comparisons were made for IOL at 38, 39, 40, and 41 weeks of gestation and expectant management. The primary analysis repeated these comparisons, limiting the population to nulliparous women with uncomplicated pregnancies and excluding those with a medical indication for IOL. We compared perinatal mortality between groups using Chi-square tests and multivariable logistic regression for all other comparisons. Adjusted odds ratios and 99% confidence intervals were reported. p < 0.01 denoted statistical significance. RESULTS: Among nulliparous, uncomplicated pregnancies at ≥37 weeks of gestation in Victoria, IOL increased from 24.6% in 2010 to 30.0% in 2018 (p < 0.001). In contrast to the preliminary analysis, the primary analysis showed that IOL in lower-risk nulliparous women was associated with increased odds of CB when performed at 38 (aOR 1.23(1.13-1.32)), 39 (aOR 1.31(1.23-1.40)), 40 (aOR 1.42(1.35-1.50)), and 41 weeks of gestation (aOR 1.43(1.35-1.51)). Perinatal mortality was rare in both groups and non-significantly lower in the induced group at most gestations. DISCUSSION: For lower-risk nulliparous women, the odds of CB increased with IOL from 38 weeks of gestation, along with decreased odds of perinatal mortality at 41 weeks only.

Perinatal outcomes after regional analgesia during labour.

BACKGROUND: Regional analgesia is a common and effective form of in-labour analgesia. However, there are concerns whether it is associated with adverse maternal and neonatal outcomes. AIMS: To examine the association between regional analgesia and maternal and neonatal outcomes. MATERIALS AND METHODS: A retrospective population-based cohort study of singleton term births in Victoria, Australia, between 2014 and 2020. Women who received regional analgesia were compared with women who did not. Multivariable logistic and linear regressions were used. RESULTS: There were 107 013 women who received regional analgesia and 214 416 women who did not. Compared to women who did not receive regional analgesia, regional analgesia was associated with an increased risk of instrumental birth (adjusted odds ratio (aOR) = 3.59, 95% CI: 3.52-3.67), caesarean section (aOR = 2.30, 95% CI: 2.24-2.35), longer duration of the second stage of labour (ß coefficient = 26.6 min, 95% CI: 26.3-27.0), Apgar score below seven at five minutes (aOR = 1.30, 95% CI: 1.21-1.39), need for neonatal resuscitation (aOR = 1.44, 95% CI: 1.40-1.48), need for formula in hospital (aOR = 1.68, 95% CI: 1.65-1.72), and the last feed before discharge not exclusively from the breast (aOR = 1.59, 95% CI: 1.56-1.62). CONCLUSION: Regional analgesia use in labour was associated with adverse maternal and neonatal outcomes. These findings may add to the risk-benefit discussion regarding regional analgesia for pain relief and highlight the importance of shared decision-making. Further large prospective studies and randomised controlled trials will be useful.

Elective induction of labour at full-term gestations and childhood school outcomes.

AIM: To explore the association between induction of labour at full-term gestations in low-risk nulliparous women and childhood school outcomes. METHODS: A retrospective whole-of-population cohort study linking perinatal data to educational test scores at grades 3, 5 and 7 in Victoria, Australia. Low-risk nulliparous women with singleton pregnancies induced at 39 and 40 weeks without a medical indication were compared to those expectantly managed from that week of gestation. Multivariable logistic regressions were used as well as generalised estimating equations on longitudinal data. RESULTS: At 39 weeks, there were 3687 and 103 164 infants in the induction and expectant arms, respectively. At 40 weeks' gestation, there were 7914 and 70 280 infants, respectively. Infants born to nulliparous women induced at 39 weeks' gestation had significantly poorer educational outcomes at grade 3 (adjusted odds ratio (aOR) = 1.39, 95% confidence interval (CI): 1.13-1.70) but not grades 5 (aOR = 1.05, 95% CI: 0.84-1.33) and 7 (aOR = 1.07, 95% CI: 0.81-1.40) compared to those expectantly managed. Infants born to nulliparous women induced at 40 weeks had comparable educational outcomes at grade 3 (aOR = 1.06, 95% CI: 0.90-1.25) but poorer educational outcomes at grades 5 (aOR = 1.23, 95% CI: 1.05-1.43) and 7 (aOR = 1.23, 95% CI: 1.03-1.47) compared to those expectantly managed. CONCLUSIONS: There were inconsistent associations between elective induction of labour at full-term gestations in low-risk nulliparous women and impaired childhood school outcomes.

The 5-minute Apgar score and childhood school outcomes.

AIM: To examine the association between Apgar score at 5 min and childhood developmental and educational outcome. METHODS: A population-based data linkage study of births ≥37 weeks' gestation linked to developmental outcomes at preparatory school and educational outcomes at school grades 3, 5 and 7 in Victoria, Australia. Multivariable logistic regressions and generalised estimating equations were used. RESULTS: There were 167,126 singleton infants with developmental results and 392,933 singleton infants with at least one educational result. There was an inverse relationship between Apgar score at 5 min and poor developmental and educational outcomes, with the worst outcomes among Apgar scores of 0-3. Apgar scores of 7, 8 and 9 were all associated with poorer developmental outcomes (aOR = 1.31, 95% CI: 1.12-1.54; aOR = 1.17, 95% CI: 1.05-1.29; aOR = 1.08, 95% CI: 1.02-1.13 respectively), while Apgar scores of 7 and 8 were associated with poorer educational outcomes at grades 3, 5, and 7. With progression through grades 3, 5, and 7, the extent of the difference in educational outcomes diminished (e.g. for Apgar scores of 0-3: aOR = 3.33, 95% CI: 1.85-6.00 in grade 3 and aOR = 1.49, 95% CI: 0.75-2.96 in grade 7). CONCLUSION: Apgar scores below 10 at 5 min are associated with poorer developmental and educational outcomes in school.

Does detection of fetal growth restriction improve neonatal outcomes?

AIM: Timely delivery of fetal growth restriction (FGR) is a balance between avoiding stillbirth and minimising prematurity. We sought to assess the neonatal outcomes for babies suspected of FGR, both true and false positives. METHODS: This population cohort study examined all singleton births in Victoria, Australia from 2000 to 2017 (n = 1 231 415). Neonatal morbidities associated with neonatal intensive care unit (NICU) admission were assessed for babies born ≥32 weeks' with severe FGR (<3rd centile) and babies with birthweight ≥10th centile who were iatrogenically delivered for suspected FGR. RESULTS: Babies with severe FGR iatrogenically delivered for suspected FGR were more likely to require NICU admission than babies with severe FGR who were not detected (3.0% vs. 1.1%, P < 0.001). After adjusting for potential confounders, the odds of NICU admission were increased (adjusted odds ratio (aOR) = 3.00, 95% confidence interval = 2.45-3.67; P < 0.001). Rates of NICU admission were also higher in ≥10th centile babies iatrogenically delivered for suspected FGR than for ≥10th centile babies who entered labour spontaneously (1.8% vs. 0.5%, P < 0.001). After adjustments, the odds of NICU admission were increased (aOR = 3.91, 95% confidence interval = 3.40-4.49; P < 0.001). NICU admissions were associated with morbidities related to iatrogenic prematurity. CONCLUSIONS: Detection and planned delivery of FGR reduces stillbirth but may be associated with increased neonatal morbidity related to iatrogenic prematurity.

Preventing harm: A balance measure for improving the detection of fetal growth restriction.

BACKGROUND: Increasing the detection of fetal growth restriction (FGR), while reducing stillbirth, also leads to unnecessary early intervention, and associated morbidity, for normally grown babies who are incorrectly suspected of FGR. AIMS: We sought to design a balance measure that addresses the specificity of FGR detection. METHODS: A retrospective cohort study on all singleton births ≥32 weeks gestation in 2016 and 2017 in Victoria. We compared two balance measures for the detection of FGR, defined as the proportion of all babies iatrogenically delivered before 39 weeks gestation for suspected FGR that had a birthweight ≥10th centile (balance measure 1) or ≥25th centile (balance measure 2). Hospital level performance on each balance measure was derived and compared to an existing performance measure for severe FGR detection in Victoria. RESULTS: Of the 38 hospitals analysed, 12 (32%) had a favourable performance on an existing indicator of FGR detection, seven (18%) hospitals had a favourable performance on balance measure 1, and 15 (39%) had a favourable performance on balance measure 2. There was a moderate correlation between hospital performance on the existing indicator and on balance measure 1 (r = 0.447, P = 0.005) but not balance measure 2 (r = -0.063, P = 0.71). There was no difference in perinatal mortality between high performing hospitals and low performing hospitals. CONCLUSION: Introducing a balance measure into routine reporting may bring greater awareness to the unintended harm associated with increased detection of FGR.

Objective measures of smoking and caffeine intake and the risk of adverse pregnancy outcomes.

BACKGROUND: In pregnancy, women are encouraged to cease smoking and limit caffeine intake. We employed objective definitions of smoking and caffeine exposure to assess their association with adverse outcomes. METHODS: We conducted a case cohort study within the Pregnancy Outcome Prediction study to analyse maternal serum metabolomics in samples from 12, 20, 28 and 36 weeks of gestational age. Objective smoking status was defined based on detectable cotinine levels at each time point and objective caffeine exposure was based on tertiles of paraxanthine levels at each time point. We used logistic and linear regression to examine the association between cotinine, paraxanthine and the risk of pre-eclampsia, spontaneous pre-term birth (sPTB), fetal growth restriction (FGR), gestational diabetes mellitus and birthweight. RESULTS: There were 914 and 915 women in the smoking and caffeine analyses, respectively. Compared with no exposure to smoking, consistent exposure to smoking was associated with an increased risk of sPTB [adjusted odds ratio (aOR) = 2.58, 95% CI: 1.14 to 5.85)] and FGR (aOR = 4.07, 95% CI: 2.14 to 7.74) and lower birthweight (ß = -387 g, 95% CI: -622 g to -153 g). On univariate analysis, consistently high levels of paraxanthine were associated with an increased risk of FGR but that association attenuated when adjusting for maternal characteristics and objective-but not self-reported-smoking status. CONCLUSIONS: Based on objective data, consistent exposure to smoking throughout pregnancy was strongly associated with sPTB and FGR. High levels of paraxanthine were not independently associated with any of the studied outcomes and were confounded by smoking.

The association between intrapartum interventions and immediate and ongoing breastfeeding outcomes: an Australian retrospective population-based cohort study.

BACKGROUND: The use of intrapartum interventions is becoming increasingly common globally. Interventions during birth, including caesarean section (CS), epidural analgesia and synthetic oxytocin infusion, can be important in optimizing obstetric care, but have the potential to impact breastfeeding. This study aimed to identify whether women who have certain intrapartum interventions have greater odds of unfavourable breastfeeding outcomes, both the immediate post-partum period and in the months after birth. METHODS: This was a population-based cohort study of singleton livebirths at ≥37 weeks' gestation between 2010 and 2018 in Victoria, Australia using routinely-collected state-wide data from the Victorian Perinatal Data Collection (VPDC) and the Child Development Information System (CDIS). The interventions included were pre-labour CS, in-labour CS, epidural analgesia, and synthetic oxytocin infusion (augmentation and/or induction of labour). Outcomes were formula supplementation in hospital, method of last feed before hospital discharge and breastfeeding status at 3-months and 6-months. Descriptive statistics and multivariable logistic regression models adjusting for potential confounders were employed. RESULTS: In total, 599,191 women initiated breastfeeding. In-labour CS (aOR 1.96, 95%CI 1.93,1.99), pre-labour CS (aOR 1.75, 95%CI 1.72,1.77), epidural analgesia (aOR 1.45, 95%CI 1.43,1.47) and synthetic oxytocin infusion (aOR 1.24, 95%CI 1.22,1.26) increased the odds of formula supplementation in hospital. Long-term breastfeeding data was available for 105,599 infants. In-labour CS (aOR 0.79, 95%CI 0.76,0.83), pre-labour CS (aOR 0.73, 95%CI 0.71,0.76), epidural analgesia (aOR 0.77, 95%CI 0.75,0.80) and synthetic oxytocin infusion (aOR 0.89, 95%CI 0.86-0.92) decreased the odds of exclusive breastfeeding at 3-months post-partum, which was similar at 6-months. There was a dose-response effect between number of interventions received and odds of each unfavourable breastfeeding outcome. CONCLUSION: Common intrapartum interventions are associated with less favourable breastfeeding outcomes, both in hospital and in the months after birth. This confirms the importance of only undertaking interventions when necessary. When interventions are used intrapartum, an assessment and identification of women at increased risk of early discontinuation of breastfeeding has to be performed. Targeted breastfeeding support for women who have intrapartum interventions, when they wish to breastfeed, is important.

Childhood school outcomes for infants born to women with hypertensive disorders during pregnancy.

BACKGROUND: To investigate the childhood school outcomes for infants born to women with hypertensive disorders during pregnancy. STUDY DESIGN: A retrospective population-based cohort study linking perinatal data from 2003 to 2013 to developmental scores at preparatory school and educational scores at school grades 3, 5, and 7 in Victoria, Australia. Exposures of interest were the presence of hypertensive disorders during pregnancy and iatrogenic delivery for preeclampsia. Multivariable logistic regression and generalised estimating equation models were employed. RESULTS: In total, 682,386 births ≥32 weeks' gestation were linked to 175,665 child developmental results and 412,834 with at least one educational result. Compared to infants born to women without a hypertensive disorder, infants born to women with a hypertensive disorder had no increased risk of poorer developmental outcomes at school entry but a significantly increased risk of poorer educational outcomes across grades 3, 5, and 7. Compared to infants born to women without preeclampsia, infants born to women iatrogenically delivered for preeclampsia had no increased risk of poorer developmental outcomes (aOR = 1.12, 95 % CI: 0.98-1.28) but a significantly increased risk of poorer educational outcomes at grades 3 (aOR = 1.23, 95 % CI: 1.09-1.38), 5 (aOR = 1.27, 95 % CI: 1.13-1.43), and 7 (aOR = 1.24, 95 % CI: 1.09-1.43). CONCLUSION: The presence of maternal hypertension in pregnancy, particularly where preeclampsia was the indication for iatrogenic delivery, is associated with impaired school educational outcomes.

Hypertensive disorders in pregnancy - Trends over eight years: A population-based cohort study.

OBJECTIVE: To describe the incidence and trends of hypertensive disorders of pregnancy and adverse pregnancy outcomes in recent years in Victoria, Australia. DESIGN: Retrospective population-based cohort study, 2010 to 2017. SETTING: State of Victoria, Australia. PARTICIPANTS: Population-based cohort study. MAIN OUTCOME MEASURES: Incidence of hypertensive disorders and its subtypes over time. Composite of major adverse maternal and perinatal outcome. RESULTS: The incidence of hypertensive disorders (n = 36,406/614,524 pregnancies with 624,193 births) and all its subtypes has been stable, (n = 4,192/73,235 = 5.7% in 2010 to 4,601/78,576 = 5.9% in 2017). Compared to no hypertension, hypertensive disorders were associated with medically-initiated birth (aOR 4.70 [4.56, 4.84]), caesarean section (aOR 1.46 [1.43, 1.50]), placental abruption (aOR 1.94 [1.69, 2.22]), maternal intensive care or high-dependency unit admission (aOR 6.80 [6.45, 7.17]), composite of major adverse maternal outcome (aOR 3.87 [3.70, 4.04]), and composite of major adverse perinatal outcome (aOR 1.63 [1.56, 1.70]). The worst maternal and perinatal outcomes were among women with superimposed and early preterm preeclampsia. CONCLUSION: The incidence of all hypertensive disorders in pregnancy has remained stable over time. Early-onset preeclampsia and superimposed preeclampsia were most strongly associated with adverse pregnancy outcomes.

Routine first trimester combined screening for preterm preeclampsia in Australia: A multicenter clinical implementation cohort study.

OBJECTIVE: To assess pregnancy outcomes following first trimester combined screening for preterm preeclampsia in Australia. METHODS: We compared pregnancy outcomes of women with singleton pregnancies who underwent first trimester combined preeclampsia screening with the Fetal Medicine Foundation algorithm between 2014 and 2017 in Melbourne and Sydney, Australia, with those from women who received standard care. The primary outcomes were preterm preeclampsia and screening performance. Effect estimates were presented as risk ratios with 95% confidence intervals. RESULTS: A total of 29 618 women underwent combined screening and 301 566 women received standard care. Women who had combined screening were less likely to have preeclampsia, preterm birth, small neonates, and low Apgar scores than the general population. Women with high-risk results (≥1 in 100) were more likely to develop preterm preeclampsia (2.1% vs. 0.7%, risk ratio [RR] 3.04, 95% CI 2.46-3.77), while low-risk women (risk <1 in 100) had lower rates of preterm preeclampsia (0.2% vs. 0.7%, RR 0.26, 95% CI 0.19-0.35) and other pregnancy complications. Screening detected 65.2% (95% CI 56.4-73.2%) of all preterm preeclampsia cases, with improved performance after adjustment for treatment effect. CONCLUSIONS: First trimester screening for preeclampsia in clinical practice identified a population at high risk of adverse pregnancy outcomes and low-risk women who may be suitable for less intensive antenatal care.